I haven’t been using brush pens to color solid areas, so I
haven’t tried the blender pen as described. But lately I’ve been experimenting
with using the Tombow colorless blender as a wash mechanism with interesting
results. (More on this later.)

5/5/12, fountain pen, Tombow colorless blender

I’ve also lately been experimenting with an old Mont Blanc
fountain pen that I used briefly decades ago as a writing pen but never really
warmed to. As a sketching pen, I like it much better, so I took it out one day at
a coffee shop. Giving water-soluble fountain pen ink a wash with water is a
popular sketching technique, so I started wondering what would happen if I used
the Tombow blender instead of water. Since the blender pen is not as wet as a
brush with water, I can’t get the elegant feathery washes that are (usually
accidentally) possible with water. But conversely, the solid Tombow marker tip
makes it possible to control the wash to a finer degree, which makes shading
easier to control.